Danish Work on Alternaria and Stemphylium

Abstract

IN the preface to this valuable work, the author explains the circumstances which led him to the study of the genera Alternaria and Stemphylium. As plant pathologist to the seed firm of J. E. Ohlsens Enke, he appears to have enjoyed absolute freedom with regard to research and every facility for carrying it out. Working in collaboration with the seed-testing laboratory of the firm, he was thus provided with a unique opportunity of studying seed-borne fungi, among which Alternaria and Stemphylium play an important part. Every year he examined several thousand seed lots, made isolations, carried out inoculation experiments, and studied the morphology of the various species. The results of his studies are presented in this monumental work of 560 pages, copiously illustrated and well reproduced. The author's approach to the problem of these genera was to study the living fungi. Starting with single-spore isolations, he selected from five to ten isolates one fully representative of the species as it occurred on the natural substratum, and so far as possible he isolated each species from several hosts and in many instances at several different times from the same host. He also obtained cultures from the Centraalbureau voor Schimmelcultures, Baarn. His examinations comprised morphological characters, physiological tests on temperature requirements and sporulation, and pathogenicity tests carried out on ten species of seedlings representative of ten families grown in wide test-tubes containing filter paper and about 10 c.c. water. The rows of test-tubes were placed in racks covering the wall. The main result was recorded twelve days after inoculation, but the incubation period was sometimes extended to eighteen days, five degrees of pathogenicity being recognized. These investigations are recorded in the special part of the volume comprising some 300 pages.

Danish Species of Alternaria and Stemphylium Taxonomy, Parasitism, Economical Significance.

By Paul Neergaard. (Communication from the Phytopathological Laboratory of J. E. Ohlsens Enke, Copenhagen.) Pp. 560. (Copenhagen: Einar Munks-gaard; London: Oxford University Press, 1945.) 60s. net.